What is Operational Carbon in buildings?

Learn about operational carbon emissions, what causes them in the built environment, and how we can reduce them.

Operational Carbon vs. Embodied Carbon

Our buildings are responsible for two types of emissions: operational and embodied. Operational carbon is the carbon emitted through the day-to-day activities of a building – whether that’s heating, cooling or ventilation, the running of key infrastructure like lifts or the powering of electronics and appliances. Simply put, operational carbon is what keeps a building’s lights on.

Embodied carbon, on the other hand, is all the other carbon emitted by a building over its life cycle, including sourcing its materials, the construction process and, finally, demolition. This blog is going to focus on how we can reduce our operational emissions, but you can learn more about embodied carbon here.

in 2018 71% of the UK built environment’s carbon footprint came from its operational emissions

Why do we need to reduce Operational Carbon and what are its main causes?

As of 2018, according to UKGBC’s Net Zero Whole Life Carbon Roadmap, 71% of the UK built environment’s carbon footprint came from its operational emissions. Operating our offices, shops and other non-domestic buildings emitted 39.7 MtCO2e, with our homes having an even larger impact at 84.8 MtCO2e. To put these emissions in context, just operating the UK’s buildings puts as much carbon into the atmosphere as burning 288 million barrels of oil each year. The main causes of these emissions are:

Fossil fuel heating in both homes and businesses

Fossil fuel driven electricity powering lights and appliances

Inefficient buildings that leak valuable energy – particularly in winter.

With a rapidly changing climate, we have a responsibility to reduce these emissions – and the good news is that the solutions are already out there. We just need to mobilise our industry and policymakers to roll-out at scale.

Learn more about reducing reliance on fossil fuel powered electricity here.

Reducing operational carbon in different building types

Operational Carbon - home with solar panels and a heat pump uk.

Existing Homes

We can reduce operational energy use in existing homes in three main ways:

Insulation: The more efficient a building, the less energy it needs to keep warm and safe. We primarily improve a home’s efficiency through insulation in areas like: cavity walls, underfloor recesses and the roof. Additional efficiency measures like double glazed windows also help reduce precious heat leaching from a home, and reduce the energy needed to keep it warm.

Switching to Electric Heating: 85% of UK homes use a gas-boiler for heating. Switching to an electricity powered heat pump is an opportunity for millions to move away from burning fossil fuels and drastically reduce their carbon footprint.

Using Renewable Energy: Where possible, homes should seek to use renewable energy to power their electricity – whether that’s through renewable tariffs or on-site generation like roof-top solar panels.

Learn more about retrofitting existing homes to be friendlier to the planet here.

Existing Non-Domestic Buildings

We can reduce operational energy use in existing non-domestic buildings by:

Moving away from Fossil Fuel heating: As of 2018, 66% of commercial buildings’ emissions were from heating – by switching to electric systems non-domestic spaces can drastically reduce their impact on the environment.

Introducing Building Performance Targets: Having targets for non-domestic buildings to improve their energy efficiency that include mandatory disclosure of their performance would galvanise action in this sector. Further building these targets into legal and commercial frameworks would raise the standard for buildings – ensuring all non-domestic buildings were having a limited impact on the environment.

Embracing on-site Renewables: Many non-domestic developments such as warehouses, factories and shopping centers have large flat roofs that are ideal for solar PV.

New Buildings

We can reduce operational energy use in new buildings by:

Putting energy efficiency first: All new buildings should be built with their energy performance in mind, ensuring that they are built as efficiently as possible to reduce future carbon emissions. This doesn’t just mean designing a home to keep it warm, but also designing it to keep it cool – so that extra energy won’t be needed for air conditioning in the future.

Prioritising electricity: Of course, this means designing with a heat pump from the start and building solar panels into the roof, but it can also mean building in smart features that automatically save electricity.

Learn more about standards for building new homes with low carbon emissions here.

What is industry already doing?

Net Zero Carbon Buildings Standard

Launched in late 2024, the Net Zero Carbon Buildings Standard aims to create a robust, universal standard for all building types that allows industry to prove their projects are net zero and in line with the UK’s climate targets. As part of this standard, limits are set for the operational energy use in buildings and targets for on-site renewable energy generation. These limits are encouraging asset designers, builders and owners to considerably reduce their operational energy use in order to meet Net Zero.

What is UKGBC doing about Operational Carbon?

Our team has long been working on projects related to helping industry reduce operational carbon emissions in both new and existing buildings. Some key activities include:

Renewable Energy Procurement: This work stream gives asset owners clear guidance on how to procure renewable energy and gives guidance on how to reimagine energy use and a flexible grid as we shift towards on-site generation and away from fossil fuels. Learn more here.

Retrofit: Reducing energy use in existing homes through energy efficiency improvements has been a long-term aim for UKGBC. We work with both national and local policy makers to implement programmes that lead to the retrofit of homes to keep them safe, warm and cheap to run. In fact, home retrofit is a great example of climate friendly fixes – like reducing operational carbon – having positive social, health and financial benefits too. Learn more here.

Operational Optimisation Labs: Throughout 2024 and 2025, UKGBC has been working to understand how optimising commercial buildings can reduce operational carbon emissions. Optimising a building, as opposed to undertaking a deep retrofit, is unobtrusive and can still lead to considerable carbon reductions without a building being taken out of us. The final outcome of this project will be launched in the spring, and you can find out more about the project and its supporters here.

Advancing Net Zero

Created in 2018 as part of a World Green Building Council initiative, UKGBC’s Advancing Net Zero programme has a mission to lead the UK’s transition to a net zero built environment. It has produced leading guidance such as the Net Zero Carbon Buildings Framework and the Net Zero Whole Life Carbon Roadmap, whilst working with organisations and experts across the industry.